Insect-plant interactions in pest management: a case study of Lipaphis erysimi (Kalt.) and its cruciferous hosts

摘要

(E)-beta-farnesene (EBF) along with extracts of host plants including 3-butenylisothiocyanate in ether caused Lipaphis erysimi to move away from feeding sites. Ether extracts of Brassica juncea and B. napus along with EBF were equal in eliciting analarm response in the aphid. Extracts from B. juncea elicited a higher alarm response than stimuli from other host plants and 3-butenylisothiocyanate. The effects were observed to last only 2-5 min. However, when acetone and cyclohexanone were used as propellants through a slow release cartridge, the effects lasted up to 12 h in an inverted funnel, although at a lesser magnitude. In another set of experiments, Eruca sativa [E. vesicaria], which is not a preferred host of the aphid, was grown in the field (in Punjab, India) in alternating rows with B. juncea in 1:1 to 1:4 row combinations. The number of colonizing aphids/plant of B. juncea varied between 3.5 to 8.5 on the 1st to 4th row away from that of E. sativa, while there were 15.8 aphids/plant inthe pure stand of B. juncea. The maximum infestation varied between 25 and 77.5 (1:1 to 1:4) to 95% in the pure stand. In a third set of experiments, L. erysimi was found to colonize all the growth stages of susceptible cultivars (BSH-1 (B. campestris) and RLM 619 (B. juncea)), while the comparatively resistant cultivars YSRL-9 and PBR-91 (B. juncea) and GSL-1 and GSL-2 (B. napus) attracted colonizing aphids only at the bud and flowering stages.